Please confirm whether the API result is success or not. Once the API result is success, you can check the bond device count by API CyBle_GapGetBondedDevicesList. Please share your project to recreate the issue.

To remove the bonding information, disconnect the connection and during the advertising we can remove the bonding information. Please refer Day015_Bonding Project in the GitHub for more information on storing and removing of the bonded data.